Chapter 2 part A Flashcards
How is temperature closely related to internal energy ?
Internal Energy consists of two main components: Kinetic E and Potential E. Temperature is closely related to the kinetic part since temperature is a measure of the average kinetic E. Therefore, the faster the molecules in a substance move (i.e., the higher their kinetic energy), the higher the temperature of the substance.
At absolute zero (0k) what would the internal energy related to kinetic motion look like?
At absolute zero (0 K), the internal energy related to kinetic motion would be at its minimum, with atomic motion ceasing.
At cooler temperature, what would the internal energy related to kinetic motion look like?
Slower atomic motions: cooler temperatures
True or False?
Heat is the measure of how “hot/cold” a substance is
False
Energy transferred between objects due to a temperature difference
BUT NOT the measure of how “hot/cold” a substance is
What type of heat is the associate to change in temperature and the heat exchange we can feel?
Sensible heat
Which type of heat is required for phase transition of a substance?
Latent Heat
What explains that oceans take longer to heat up in summer?
Water has a much higher specific heat than air (by a factor of four). Oceans take longer to heat up in summer but are also slower to cool in winter (compared to heating/cooling of air).
By what factor does specific heat capacity of air & water differ?
Water has a much higher specific heat than air (by a factor of four)
What are the different phases & their associated molecular configurations?
Solid: Compact, ordered structure.
Liquid: Compact, disordered state.
Gas: Low-density, disordered state.
What phase changes of H20 cools the environment?
Heat absorption of H20 happens in melting & evaporation
Ice → Liquid (melting).
Ice → Vapor (sublimation).
Liquid → Vapor (evaporation)
What phase changes of H20 warms the environment?
Heat Release: freezing & condensation
Liquid → Ice (freezing).
Vapor → Ice (deposition).
Vapor → Liquid (condensation).
How is latent heat an important driver for global circulation?
Transport of water vapour followed by release of latent heat at different locations in the atmosphere
What is the importance of Latent Heat in Atmospheric Processes?
Condensation and freezing (release heat)
-Cumulus cloud convection
-Mid-latitude cyclones and hurricanes.
-Global circulation through water vapor transport and heat release.
Evaporation: from Earth’s surface and from clouds / precipitation cools the air and supplies moisture to the air (increasing the humidity).
What are the mechanisms for heat transfer in the atmosphere
*Conduction(molecular motion - ex: air nea the Earth’ surface)
*Convection (macroscopic fluid motion)
*Radiation(electromagnetic waves- ex: energy from the sun)
Which substances have faster molecular motion? Why?
Warmer substances
-translation
-rotation
-vibration
Why is conduction a molecular transfer of heat from warm to cold regions?
Collisions with near by molecules imparting momentum and energy
What is thermal conductivity?
Thermal conductivity: efficiency in transferring heat by molecular motion
Good vs poor conductors
Good conductors conduct heat more efficiently: Silver & copper are excellent conductors
Poor conductors are good insulators: Air is a rather poor conductor
Define the components convection is seperated in, in atmosphere
*Advection: transfer by bulk air motion (horizontal or vertical transport by the wind)
*“Atmospheric” convection: turbulent vertical circulations driven by buoyancy (density) differences
Define air parcel
A coherent sample of air that moves freely but does not exchange heat with its surroundings
Maintains the same pressure (but not temperature or density) as its surroundings at the same height
Imagine a balloon floating through the air
What determines air parcel’s vertical motion?
Density (positively vs negatively buoyant)
How does temperature of parcel affect buoyancy?
Warmer parcels are less dense/lighter (positively buoyant)
Colder parcels are more dense/heavier (negatively buoyant)
Which mechanism for heat tranfer in the atmosphere explains: Light air rises, dense air sinks
Atmospheric Convection
What does conservation of E=0 describe?
0 = “work done on surroundings” + “internal energy gained by air parcel
*Here, heat exchange term is zero, since no heat is added/remove
Why/when do air parcels expand? How does that affect conservation of E? Opposite?
Air parcels in rising branches move into lower pressure
To equilibrate pressure with surroundings, they must expand
Expansion takes work, which, from conservation of energy, causes a loss of internal energy and cooling
*Opposite happens with sinking air parcels
Sensible VS Latent heat
Sensible Heat: The heat that causes a temperature change in a substance, directly related to the kinetic energy of molecules.
Latent Heat: The energy absorbed or released during a phase change (solid, liquid, gas) without changing the temperature.
What are the phase changes of water and how do they affect heat exchange with the environment?
Melting (Ice → Liquid): Absorbs heat, cools the environment.
Sublimation (Ice → Vapor): Absorbs heat, cools the environment.
Evaporation (Liquid → Vapor): Absorbs heat, cools the environment.
Freezing (Liquid → Ice): Releases heat, warms the environment.
Deposition (Vapor → Ice): Releases heat, warms the environment.
Condensation (Vapor → Liquid): Releases heat, warms the environment.
What drives atmospheric convection, and why is it important?
Atmospheric convection is driven by buoyancy, where warm, less dense air rises, and cool, denser air sinks.
Important for:
-cloud formation
-weather pattern
-vertical transfer of heat in the atmosphere
What is an adiabatic process, and how does it affect an air parcel?
An adiabatic process is one where no heat is exchanged between an air parcel and its surroundings.
As a parcel rises, it expands and cools due to lower pressure. Conversely, as it sinks, it compresses and warms due to higher pressure.
How does wind chill affect the perceived temperature of the human body?
Wind chill increases the rate of heat loss from the body by removing the insulating warm air layer over the skin through wind (advection). It also increases evaporation from the skin, making it feel colder than the actual temperature.
What role does latent heat play in cloud formation?
When moist air rises and cools, water vapor condenses into liquid droplets, releasing latent heat. This released heat warms the surrounding air, increasing its buoyancy and further promoting upward convection, essential for cloud development.
